Airplane wing



R. D. BALLMANN April 21, 1936.

AIRPLANE WING Filed Oct. v29, 1954 5 Sheets-Sheet l IN VENTOR.

April 21 1936- R; D. BALLMANN 2,038,337

AIRPLANE WING Filed oct. 29, 1954 s sheets-sheet 2 FLG.5v y INVENTOR.

A-Plil 21., 1936 R. D. BALLMANN 2,038,337'

AIRPLANE WING Filed oct. 29, 1954 s sheets-sheet s `Patented Apr. 21, 1936 yUNITEDV STATES AmPLANE WING l Ralph D. Ballmann, Cincinnati, Ohio 1 Claim.

An object of my invention is to produce an airplane wing capable of expansion and contraction lengthwise whereby conservation of storage' space in hangars is attained, together with certain attainments in alteration of speed, take-off and landing characteristics.

'I'hese and other objects'are attained in the airfoil construction described in the following specification and illustrated inthe accompanying drawings, in which: l l

Fig. 1 is a plan view of a characteristic airfoil construction embodying my invention, on a materially reduced scale.

Fig. 2 is a slightly enlarged and somewhat diagrammatic sectional view of one part of the wing shown in Fig. 1, to illustrate the manner of telescopic arrangement of wing sections, not intended to disclose details of structure, and taken on line 2-2 of Fig. 1.

Fig. 2a is a materially enlarged fragmental sectional view of the extended relationship which exists when wing sections are moved to the positions shown in Fig.- 1 and somewhat in such a location through the wing keys and keyways as is found on line 2a-2a of Fig. 4.

Fig. 3 is a transverse sectional view of the nested wing sections when telescoped to minimum spread positions and taken along a position some- 'I'he airfoil embodying my invention is corn-A posed of as many telescoping sections II, I2, and I3 on one side of a central section II and as many sections I I, I5, and I6 on the opposite side of central section I1 as may be desired, in keeping with the size of the plane, the purpose for which it is designed, and the like. While sections II and I6 telescope into the respective sections I2 and I5, and sections I2 and I5 telescope into the respective sections I3 and Il, the telescoping of sections I3 and I4 into central section I1 will reduce the wing to the utmost of minimum dimensions approximating no greater size than the spread of the landing gear. In this manner extreme economy of hangar is attained.

Application october 29, 1934, serial No. '150,410

So that the airfoil sections may be properly' guided and locked in outward and inward movements and limitations thereof, I provide along the nose and trailing edges ofthe wing sections a series of keys "I8 and I9 respectively which extend beyond the surfaces of the sections and are shaped to engage correspondingly shaped keyways 20 and 2| respectively formed inthe inside surfaces of the respective nose and trailing edges of the wing sections. These keys, as shown in lo Fig. 2a, engage abutments 22 at the outer ends of the wing sections, thereby limiting outwardV movement of the sections to produce the completely expanded airfoil, while inward collapsing movement of the sections is limited by abutment 15 ofthe keys against each other and by abutment of sections I3 and I4 at their inner ends within central section I1, obviously, central section I1 is the one to which` the body, cabin or cockpit elements of the plane are attached. o I shall now describe the wing structure which 2 comprises the spars, and surface material of each section. Preferably, the nose and trailing edge of each section, at the location of the key thereof, is made' of skeleton reenforced spars 23 and 2l respectively of solid or suitably light and strong material extending to and terminating the immediate curvature of the nose and trailing edge, as Figs. 3 and 4 disclose. Between these, the under and upper surface parts of the sections are 0 made up of ribs 25 at properly spaced intervals extending transversely from nose t'o trailing edge and fastened to the spars to fonn the framework of each section, over the outer surface of which suitable wing covering material 26 is placed and 35' 4 properly secured. I prefer to have this material consist of corrugated metal of suitable alloy, guage, and corrugation, with ribs and spars of the same metal so that unitary welding or other appropriate fastening may be included through- 40 out the fabrication of each section. Also I have found that placement of the corrugated covering is preferable with the corrugations extending longitudinally of the airfoil, as shown in Fig. 6, so

as to cross the ribs, thereby aiding in section 45 strengthening effect.

I prefer ribs of triangular cross sectional shape and hollow, so as to create the greatest degree of strength possible, both torsional and bending, with pronounced reduction of mass and conse- 50 quent weight because of such hollow formation, as well as economy of material needed in such elemen'ts.

Fig. 6, which has not included the key and keyway features described, is a modification designed 55 primarily to show that both nose and trailingedge spars may be of sheet metal, to which the attened rib ends may be attached, as by welding. Also, this view shows how the covering material may extend completely around the outer surfaces of each wing section, with corrugations extending in a. longitudinal direction.

Having thus described my invention what I claim is:

An airplane wing consisting of-a. series of sections telescopically interrelated, each section consisting of a spar forming the nose edge, a spar forming the trailing edge, a series of spaced upper surface ribs, a series of spaced under surface ribs, said series being spaced apm and spacing the spars apart, whereby a section-receiving space encompassed by the ribs and spars is formed, said sections having relative sizes permitting of telescoping interrelation, keys splined on the spars and uniting the sections, covering material for each section, corrugated and extending transversely of the ribs, and abutments on the sections 10 relative movement of the sections.

RALPH D. BALLMANN. 

